Purification method or protocols of the viruses: HIV-1, Lassa virus, oncornavirus and other retroviruses. Protocol uses an iodixanol gradient in a sedimentation velocity mode to purifyHIV-1 virions without affecting the infectivity of the virus. In rate-zonal iodixanol gradients the HIV-1 was effectively separated both from Vif and from the microvesicles.

Protocol: M5 Velocity (rate zonal) gradients for purification and assembly analysis of viruses.